Contagious Bovine Pyelonephritis (CBP) in Cattle

Contagious Bovine Pyelonephritis (CBP) is an important infectious disease of cows all over the world. It is caused by the bacteria Trueperella pyogenes which attacks the urinary system, including the kidneys and urinary tract.

Etiology:

The main causative agent is a strain of bacteria known as Corynebacterium renale. The following factors contribute to the development and spread of this disease:

  • Bacterial Transmission:

CBP spreads through direct contact among cattle. The bacteria may be found in urine, reproductive tracts, and contaminated surfaces. Factors like close animal contact, overcrowding, and poor hygiene conditions facilitate the transmission of this bacteria.

  • Carrier Animals:

Certain cattle can carry C.renale without showing symptoms, releasing the bacteria in urine. These animals can contaminate the environment, acting as a source of infection for other animals in that area.

  • Urethral structure:

Female cattle have a relatively shorter and wider urethra, increasing the risk of bacterial attack in the urinary tract.

However, males have a longer but narrow urethra,thus have lesser risk

  • Mating:

The Breeding procedure can contribute to C.B.P transmission. During mating procedures, the bacteria present in the reproductive tract can enter the urinary tract, which can cause infection. The Unhygienic practices during artificial insemination of cattle can also facilitate these bacteria into the urinary tract of animals.

  • Management Factors:

Certain management practices may increase the risk, which include:

  • Housing on soiled bedding for a long time.
  • Inadequate cleaning of the farm.
  • Weak Immune system:

When an animal is in stress, their immune system is compromised thus making them more susceptible to bacterial infections like CBP, stress may be due to;

  • Frequent transportation from one place to another
  • Heat stress ( no proper cooling of space in summer)
  • Reaction of a drug or hormone which is administrated
  • Physical injury
  • Any other disease like mastitis etc.
  • Concurrent Diseases:

Pre-existing conditions like bladder infections or reproductive tract diseases can increase cattle’s susceptibility to CBP. These conditions provide an entry point for bacteria to infect the urinary tract.

Pathogenesis of Contagious Bovine Pyelonephritis:

  • Transmission:

The primary mode of transmission of this bacteria is through the urine content of infected cattle. The bacterium C.renale is commonly present in the genital & excretory tracts of infected animals, particularly in the kidneys and bladder. Contaminated urine can contaminate the environment, water sources & feed, allowing the spread of the bacteria to other animals. Farmers or caretakers of animals/cattle can also serve as an agent to transfer bacteria to healthy ones

  • Entrance and colonization:

The bacteria enter the urinary system of healthy cattle through the urethra and then go towards the bladder. C.renale has specific structures called fimbriae which are proteinaceous surface appendages that help in adherence to the urothelium, which helps in colonization and invasion. Once the bacteria have got to the bladder, they will proceed further into the ureters and kidneys.

  • Adherence and invasion:

The fimbriae of C.renale maintains the bond or connection to the urothelial cells lining the bladder and urinary tract of the animal. The bacteria then penetrate through the epithelial cells and multiply within the cells. This can lead to damage to tissues and thus inflammation.

  • Inflammatory response:

The invasion of C.renalale into the urinary system gives rise to an inflammatory response to the animal’s immune system. Neutrophils are recruited at the site of infection, which release various pro-inflammatory molecules and cytokines.

  • Kidney involvement:

C.renale can proceed from the bladder to the kidneys, which leads to pyelonephritis. the bacteria cause inflammation and damage to the renal parenchyma. This forms abscesses and renal scarring, which affects kidney function.

  • Chronic infection:

In some cases, CBP becomes chronic, with persistent infection and intermittent shedding of bacteria in the urine. Chronic carriers can serve as reservoirs for the disease which causes the spreading of the bacteria within a herd.

  • Pre-disposing factors:

Several factors can increase the danger of cattle getting CBP. These include

  • urinary calculi or other
  • anatomical defects
  • malnutrition

Clinical Signs of Contagious Bovine Pyelonephritis:

General Signs:

  • Anorexia
  • Less milk production
  • Weight loss
  • Urinary Signs:

  • Frequent urination
  • Painful urination
  • Hematuria
  • Cloudy or malodorous urine
  • Urinary dribbling
  • Systemic Signs:

  • Fever
  • Lethargy
  • Dehydration
  • Depression
  • Enlarged or painful kidneys

 

Treatment of Contagious Bovine Pyelonephritis:

  • Indications for Surgery:

Surgical treatment should be done in the following situations:

  1. Chronic and recurrent cases of CBP that do not respond to conservative management.
  2. Severe cases of CBP with complications such as abscess formation, hydronephrosis, or pyonephrosis.
  3. Animals with structural abnormalities of the urinary tract that contribute to the recurrence of CBP.
  • Surgical Techniques:

  1. Nephrectomy:

  2. Nephrectomy involves the complete removal of the affected kidney.
  3. This procedure is typically reserved for cases where the kidney is severely damaged and non-functional, or when medical treatment fails to control the infection.

iii. It may be performed through an open surgical approach or using minimally invasive techniques such as laparoscopy or robotic-assisted surgery.

Nephrectomy

  1. Partial Nephrectomy:

  2. Partial nephrectomy involves removing only the diseased portion of the kidney while preserving the healthy tissue.
  3. This procedure is considered in cases where there is a localized infection or when preserving renal function is crucial.

iii. Techniques such as stapling, suturing, or sealing devices may be used to control bleeding and ensure proper closure of the remaining kidney tissue.

  1. Drainage Procedures:

  2. In cases where abscesses or purulent collections are present within the kidney or urinary tract, drainage procedures may be performed.
  3. Percutaneous or surgical drainage techniques may be employed, depending on the location and size of the abscess.

iii. These procedures aim to remove the infected material and promote healing of the affected tissues.

  1. Corrective Surgery for Contagious Bovine Pyelonephritis:

  2. Structural abnormalities in the urinary tract can contribute to the recurrence of CBP.
  3. Corrective surgical procedures, such as ureteral reimplantation or reconstruction of the urethra, may be performed to restore normal urinary flow and prevent reinfection.

Nonsurgical Treatment:

 

Antibiotic Therapy:

Selection of Antibiotics:

Treatment of CBP typically involves the administration of broad-spectrum antibiotics effective against Corynebacterium renale, such as penicillins or aminoglycosides.

Before antibiotic initiation, performing a bacterial culture and sensitivity test helps identify the specific bacterial strain and determine the most appropriate antibiotic treatment.

Commonly used antibiotics include penicillin G, ampicillin, ceftiofur, enrofloxacin, and gentamicin.

Contagious Bovine Pyelonephritis Drug of Choice:

In Pakistan, the primary drug of choice for the treatment of CBP is enfloxacin. Enrofloxacin belongs to the fluoroquinolone class of antibiotics and has a broad spectrum of activity against the bacteria commonly associated with CBP, including Escherichia coli, Proteus spp., and Klebsiella spp. It is considered an effective and reliable drug for the treatment of CBP in cattle.

Mechanism of Action:

Enrofloxacin acts by inhibiting bacterial DNA gyrase and topoisomerase IV enzymes, which are essential for bacterial DNA replication, transcription, and repair. By interfering with these enzymes, enrofloxacin effectively kills susceptible bacteria, thereby treating the infection.

Dosage and Administration:

The dosage of enrofloxacin for the treatment of CBP in cattle may vary depending on the severity of the infection, the weight of the animal, and the specific formulation of the drug. 2.5 to 5 mg enrofloxacin/kg bw/day. Typically, enrofloxacin is administered either orally or via intramuscular injection.

Precautions and Considerations:

While enrofloxacin is an effective treatment option, certain precautions and considerations should be taken into account:

Withdrawal Period:

Enrofloxacin has a specified withdrawal period, which is the time required for the drug to be eliminated from the animal’s system. It is essential to adhere to the withdrawal period to ensure that the milk and meat from treated animals do not contain residues that may pose a risk to human health.

Supportive Care:

Fluid Therapy:

Maintaining proper hydration is crucial for cattle with CBP, as it helps flush out bacteria and promote urine production.

Intravenous or oral fluid therapy may be employed to correct dehydration and maintain electrolyte balance.

Electrolyte solutions containing sodium, potassium, and bicarbonate can be administered intravenously to restore normal levels.

Urinary Acidification:

Acidification of urine helps create an unfavorable environment for bacterial growth in the urinary tract.

Administering ammonium chloride orally can acidify the urine, discouraging bacterial colonization.

Regular monitoring of urine pH is necessary to ensure optimal acidification without causing harmful side effects.

 Environmental Management:

Hygiene and Sanitation:

Adequate hygiene measures are essential to prevent the spread of CBP within the herd.

Infected animals should be isolated and housed separately to minimize contact with healthy individuals.

Regular cleaning and disinfection of animal premises, equipment, and water sources are necessary to reduce the bacterial load and prevent reinfection.

Water Management:

Ensuring a clean and uncontaminated water supply is crucial for preventing the transmission of CBP.

Water sources should be regularly monitored and treated if necessary to maintain optimal water quality and prevent bacterial proliferation

 

In severe cases of CBP, surgical intervention may be necessary. Surgical treatment involves the removal of the affected kidney (nephrectomy) to eliminate the source of infection. This procedure aims to prevent further spread of the bacteria and alleviate clinical signs.

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Control Measures:

Biosecurity Measures:

  • Isolate newly introduced animals and test them for CBP before integrating them into the herd.
  • Implement strict biosecurity protocols to prevent the introduction of infected animals into the herd.
  • Maintain a clean and hygienic environment, regularly disinfecting equipment, housing facilities, and water sources.

Testing and Surveillance:

Regularly test the entire herd for CBP using appropriate diagnostic methods, such as bacterial culture and polymerase chain reaction (PCR).

Test animals showing clinical signs of CBP, such as frequent urination, blood in urine, or reduced milk production.

Develop a surveillance program to monitor the prevalence and spread of CBP within the herd.

Vaccination:

Currently, no commercially available vaccines specifically target CBP. However, vaccination against other urinary tract infections may indirectly reduce the risk of CBP.

Herd Management Practices:

Implement good herd management practices, including proper hygiene, regular cleaning of barns and facilities, and adequate ventilation.

Optimize nutrition and provide a balanced diet to enhance the immune system of animals, reducing their susceptibility to CBP.

Implement a strategic deworming program to control parasitic infections that can weaken the immune system.

Education and Training:

Educate herd owners, managers, and workers about CBP, its transmission, and control measures.

Train personnel in proper hygiene practices, including handwashing, use of protective clothing, and disinfection procedures.

Raise awareness about the importance of early detection and reporting of CBP cases to implement prompt control measures

implementing preventive measures, adhering to treatment protocols, and practicing good hygiene and biosecurity measures.

 

Zoonotic Potential

While CBP is primarily considered a disease of cattle, limited evidence suggests that C. renale may have zoonotic potential. However, it is important to note that the zoonotic transmission of CBP is rare and not well-documented. There have been a few isolated reports of human infections associated with C. renale.

Postmortem Findings :

Postmortem examinations of CBP-infected cows reveal inflamed kidneys, pus-filled abscesses, and damage to the urinary tract.

 

 

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